The present invention relates to an antenna for a mobile station; and, more particularly, to a planar microstrip patch antenna having improving antenna efficiency and high gain, and arranged for installation in a mobile station.
In recent years, mobile stations are used in both a personal communication service (PCS) and a wireless local loop (WLL) in which a different communication frequencies are used. Thus, it is necessary for an antenna to operate in frequency corresponding to each service.
Among the antennae for satisfying the above, a helical antenna is popularly used in the mobile station at the present time. One type is capable of being operated as a helical antenna at a retraction state and operated as a combination of the helical antenna and a monopole antenna in an extended state. In this antenna device, a housing of the handheld mobile station is generally used as a ground plane.
Referring to FIGS. 1A and 1B, there is shown the conventional helical antenna 100 for the mobile station, wherein each figure illustrates the antenna in a retracted state and extended state, respectively. The helical antenna of the previous art includes a rod antenna 8 having a conductive core 12 therein and a insulator 14 covering the outside of the conductive core 12, a support member 10 for supporting the rod antenna 8, made of an insulating and a non-magnetic material, a button 16 for functioning as a gripper for extending and retracting the rod antenna 8, a helical antenna 6 made of a resilient metal wire in a spiral shape, a hood 18 having an aperture 20 on the top thereof, made of an insulating and a non-magnetic material, a contact washer 22 made of metal, for being in galvanic contact with the helical antenna 6 and an abutment 28 in the transition region between the lower and upper regions of the rod antenna. The abutment 28 plays a role in lifting the contact washer 16 so that the helical wire is compressed as shown in FIG. 1B.
The connecting portion 26 is galvanically directly connected to the transceiver 2. In the active state of the helical antenna 6, the contact washer 22 abuts against the contact device 24 so that galvanic connection is obtained between the helical antenna 6 and the connecting portion 26 and thereby also direct to the transceiver 2. Whereas, in the passive state, i.e., the extended state, the helical antenna 6 is galvanically separated from the transceiver 2.
In the helical antenna device 100, there are several drawbacks such that the mobile station is hardly miniaturized because the antenna is attached on the exterior of the mobile station and a user""s head is subjected to an electromagnetic wave due to a concentration of the radiation near the center of the antenna. Moreover, the helical antenna device 100 also has a problem that radiation efficiency is decreased because the radiation of the antenna is disturbed by the user.
It is, therefore, an object of the present invention to provide a planar microstrip patch antenna for improving antenna efficiency and gain by implementing a microstrip patch formed in a shape of a zigzag conduction or an H-slot.
In accordance with one aspect of the present invention, there is provided a planar microstrip patch antenna, comprising: a substrate made of a dielectric material; a microstrip patch, made of a conductive metal, formed on the substrate; a feeding conductor to electrically connect to an end of the microstrip patch; and a ground face disposed on a side of the substrate.